As part of his continuing investigation into law enforcement requests for consumers’ mobile phone records, today Congressman Edward J. Markey (D-Mass.) sent a letter to the Department of Justice (DOJ) querying the agency about how it handles, administers and disposes of the information received from mobile phone carriers. On Monday, Rep. Markey, co-Chair of the Congressional Bi-Partisan Privacy Caucus, released responses from nine wireless carriers. The responses provided a first-ever accounting of its kind and revealed the volume and scope of requests made by law enforcement – 1.3million requests in 2011 alone – including requests for geolocation information, content of text messages, and wiretaps, among others. Rep. Markey specifically inquires in his letter about the practice of requesting “cell tower dumps”. In these data dumps, mobile phone carriers provide all the phone numbers of mobile phone users who connect with a cell phone tower during a certain period of time.

“The expansive nature of these information requests likely results in the collection of sensitive records of innocent consumers by law enforcement,” writes Rep. Markey in the letter to the Department of Justice. “The practices of law enforcement agencies, along with the enormous amount of requests, range of information provided, and large numbers of consumers involved, raise a number of important privacy concerns. It is important to know how law enforcement is handling the records of consumers, especially those who are innocent, which may be collected as part of these information requests.”

In the letter to the Justice Department, Rep. Markey requests response to questions that include:

How many requests for mobile phone records and what types of requests have the Department of Justice filed with wireless carriers during each of the last five years?

What legal standard and type of order does DOJ believe applies for each of these types of requests?

How are mobile phone records transmitted between wireless carriers and DOJ, and how and where does DOJ handle, administer, and store this information?

Does DOJ segregate the records of individuals who are not subjects of an investigation from individuals who are being targeted for investigation by law enforcement? How long does DOJ store this information and do they delete this information?

Does DOJ require any reporting by local or state law enforcement on the number or types of requests they make each year of wireless carriers for mobile phone records?

Has DOJ issued best practices or guidelines for local or state law enforcement about how to best handle, administer, and dispose of this sensitive personal information provided by the wireless carriers?